Through the source code I have seen that most of the BIG websites have no any meta tags and higher pageranks, including MSN
The description tag should defo be used, I normally make it the same as my title or maybe change it a little. Keywords are useless tho.
i agree with you 100%. i believe that google uses the meta description tag for showing in the SERPS if your site is not listed in DMOZ aka google directory. One of my sites was listed in dmoz and the google serps shows the description i used in dmoz. anothe site which was not listed in dmoz but had a description meta tag showed up the contents from that tag. a third site, in which i didnt have neither dmoz listing or desc. tag, it showed content from the page. so..i believe description tag is important after title tags. I use keyword tag to identify each page forwhich i optimise it...i have a very short memory..
It depends on how old your website is. If it has good contents then their is no use of meta tags but if you have a new site then you definitely use meta tags.
Yep, I always use meta tags. It does no harm and some search engines still use them to rank pages - any extra traffic helps.